surely you're not gonna put a 4200 up to a closed drive tranny, a healthy 235 makes them sweat!
A neat thing that you could use is a '50 thru '62 235/cast iron PG factory adapter... 235 pattern on one side and round cast iron PG pattern on the other side(they also had 265, 283,327,348 V8/cast iron PG adapters '55 thru '62). Some people on Stovebolt.com site probably have them comming out their, lets say their ears.
Good guess but not quite...
